Refrigeration



June 11, 1940. s, w, AINDERSSQN 2,204,060

REFRIGERATION Filed Dec. 22, 1937 2 Sheets-Sheet 1 IN VENTOR.

2 BY 3 I fiToRNEY.

June 11, 1940. s. w. E. ANDERSSON REFRIGERATION Filed Dec. 22, 1957 2 Sheets-Sheet 2 I Jm w- SI'NfiNTOK [m M A T r oRNEY.

. Mm ,v, u Q xwwm mm N 5 0 4- W. Y an B hh sw mm 0 @Y a E \r Y q mm m. m6 0 .1? I F kw m \\\r 0 f1! A 0 I w/ 1 g Sm 0 N &\ um mw Patented June 11, 1940 UNITED STATES PATENT OFFICE REFRIGERATION of Delaware Application December 22, 1937, Serial No. 181,091

" 10 Claims.

My invention relates to refrigeration, and more particularly to control of refrigerationapparatus.

It is an object of the invention to provide an improved control for controlling the energy sup- 5 ply of refrigeration apparatus. More particularly, it is an object of the invention to provide an improved control device for controlling the supply of gas to refrigeration apparatus of an absorption type. I accomplish this by providing 10 a control device which automatically controls the other objects and advantages thereof, will be more fully understood upon reference to the fol- 25 lowing description and accompanying drawings forming a part of this specification, and of which Fig. l more or less diagrammatically illustrates refrigeration apparatus of an absorption type provided with a control device embodying the in- 30 vention; and Fig. 2 is an enlarged vertical sectional view taken at line 2-2 of Fig. 1 to illustrate the control device more clearly.

Referring to Fig. 1, I have shown my improved control device in connection with absorption re- 35 frigeration apparatus of a uniform pressure type, generally as described in Patent No. 2,037,782 to William. R, Hainsworth, in which an auxiliary pressure equalizing gas is employed. The apparatus comprises a generator l having a rear 40 chamber II and a forward chamber I2 communicating with an upward extending stand-pipe or separator 13. The generator contains a body of absorption liquid, such as water, having a suitable refrigerant, such as ammonia, in solution 45 therein. The generator I0 is heated by a gas burner M which projects its flame into the forward end of a horizontal flue [5 which extends through the generator. A suitable combustible gas is delivered from a source of supply through 50 conduit l 6, control device H to be described hereinafter, and conduit I8 to the burner.

The heating of generator It) causes refrigerant vapor and absorption liquid in chamber II to pass through an opening I9 in the lower end of 55 the small vertical conduit 20 which constitutes a vapor-lift and conducts refrigerant vapor and absorption liquid to the upper part of stand-pipe l3. Liberated refrigerant vapor entering standpipe l3 from conduit 20, and also refrigerant vaporexpelled from solution in stand-pipe I3 and 5 chamber I2, flows upward into an air-cooled condenser 2| provided with heat transfer fins 22. The refrigerant vapor is liquefied or condensed in condenser 2| and flows through a conduit 23 into the upper end of an evaporator or cooling element 24 which is arranged in a thermally insulated storage space 25.

An inert gas, such as hydrogen, enters the lower end of cooling element 24 from an outer passage 26 of a gas heat exchanger 21. The liql5 uid refrigerant evaporates and diffuses into the inert gas with consequent absorption of heat from the surroundings of cooling element 24. The resulting mixture of refrigerant and inert gas, that is, gas rich in refrigerant, flows from coling element 24 through an inner passage or conduit 28 of the gas heat exchanger which is connected at its lower end to the lower end of an absorber 29. Refrigerant vapor in the rich gas mixture is absorbed into weak absorption liquid that enters the upper part of the absorber through a conduit 30. The heat liberated with such absorption of refrigerant vapor may be transferred to a cooling medium which flc vs through a coil 3| arranged in thermal exchange 30 relation with absorber 29.

The hydrogen or inert gas, which is practically insoluble and weak in refrigerant vapor, flows upward from absorber 29 through the outer passage 26 of the gas heat exchanger into the lower end of cooling element 24. The absorption liquid flowing downward through absorber 29 becomes enriched in refrigerant vapor and flows through a conduit 32 and outer passage of a liquid heat exchanger 33 to chamber ll of the generator l0. Refrigerant vapor and absorption liquid flow upward through conduit 20 into the upper part of stand-pipe l3, as explained above, and absorption liquid weak in refrigerant flows from chamber 12 through the inner passage or conduit of liquid heat exchanger 33 and conduit 30 into the upper part of absorber 29.

The lower endof condenser 2| is connected by conduit 23, vessel 34, and conduit 35 to the gas circuit, as at the upper end of conduit 28, for example, so that any inert gas which may pass through the condenser can flow to the gas circuit and not be trapped in the condenser. Any refrigerant vapor not liquefied in the condenser will flow upward in conduit 23 to displace inert 5 gas in vessel 34 and force such gas through conduit 35 into the gas circuit, thereby increasing the total pressure in the system. With such in crease in pressure in the system, an adequate condensing pressure is obtained to insure condensation of refrigerant vapor in condenser Zll.

In accordance with my invention the flow of gas to burner M is controlled by the control device I l. The control device ii comprises a casing 36 having inlet and outlet openings 31 and 38 to which are connected conduits it and 98, respectively. A resilient or movable diaphragm 39 is secured at its peripheral edge between the two parts of casing 35 to form an upper chamber AB and a lower chamber ii, and in the lower chamber 4| is provided a partition 42 having an opening to form a main passage for flow of gas from inlet 37 to outlet 38.

Within the opening in partition $2 is fixed a short sleeve member 43 which serves as a seat for a valve M having a stem t5 secured to diaphragm 39. The valve member it controls the flow of gas to burner id in response to a thermal element lt which is located in chamber 30.

The thermal element 46 is in the form of an expansible diaphragm and is secured to and in communication with a hollow hub member ii. To the hub member 41 is connected one end of a tube 38 which extends through an opening in a cover plate 49 and is connected to a thermal bulb 50. The bulb 51B is arranged in thermal exchange relation with cooling element 2d, as shown in Fig. 1. The hub member il is fixed to a resilient diaphragm 5! which is secured between the upper end of casing 36 and cover plate 49. The cover plate 49 is provided with a temperature adjustment knob 52 for adjusting the position of resilient diaphragm 5i and hence the operating position of thermal element $6.

The thermal element 46, tube at, and bulb are charged with a suitable volatile fluid and constitute an expansible fluid thermostat. The thermal element 46 expands and contracts with an increase and decrease of temperature, respectively, and these movements are utilized to regulate valve member 44 and control the flow of gas to burner It, as will be described hereinafter.

The structure in chamber Ml for transmitting movements of thermal element at to valve member 44 includes a lever 53 having a knob 5% against which the thermal element 65 is adapted to hear. The lever 53 is pivoted at one end at 55 to a wall of casing 36 and the other end engages a lip or stop 56 formed at the end of a second lever 51. The lever 51 is also pivoted at 55 to the wall of casing 36 and an intermediate portion thereof bears against an upwardly extending extension 53 of valve stem 55.

The outer end of lever 51 adjacent the stop 56 is provided with a downwardly extending hollow sleeve portion 59 which is internally threaded to receive an adjustment screw 60. A coil spring BI is disposed between the outer end of lever 53 and adjustment screw 60 to spread the levers 53 and ti apart. By removing an outer screw 32, the inner adjustment screw is accessible from the exterior of casing 36 for adjusting the tension of spring M.

A second coil spring 53 is disposed between the outer end of lever 53 and a cup-shaped adjustment screw 65. The adjustment screw M is movable in a threaded opening formed in a boss 55 on casing 36. By removing an outer screw 56, the adjustment screw 54 is accessible from the aeoaoeo the exterior of casing 36 for adjusting the tension of coil spring 63.

The operation of the control device just described is substantially as follows: When the cooling element 24 tends to rise above a desired low temperature, the volatile fluid in the expansible fluid thermostat increases in volume whereby thermal element it expands. With expansion of thermal element 46 the lever 53 is moved downward. Since the levers 53 and Eli are spread apart by coil spring bl, downward movement of lever 53 imparts downward movement to lever ill. The lever 57 moves the extension 58 downward against the gas pressure on the underside of diaphragm 39, thereby increasing the opening of valve member dd. With an increase in the opening of valve member at, gas is delivered at an increased pressure to burner it and additional heat is applied to generator it whereby. the amount of cold produced by cooling ele ment 2!; is increased.

When cooling element 24 tends to fall below the desired low temperature, the volatile fluid of the expansible fluid thermostat becomes reduced in volume and thermal element id contracts. Due to the gas pressure on the under-side 01" diaphragm 39, valve member Mi moves toward its closed position with contraction of thermal element M5, the, levers 53 and 5? moving upward together with valve member at, diaphragm 3d, and extension 58. With valve member ll-t moved toward its closed position, gas is delivered at a reduced pressure to burner i i and less heat is applied to generator l0 whereby the production of cold by cooling element 24 is reduced.

By controlling valve member 4d and hence the flow of gas to burner M in response to thermal element M5 in the manner just described, the

operation of the refrigeration apparatus is effectively controlled whereby cooling element 24 is capable of maintaining the thermally insulated space 25 substantially at a desired low temperature or temperature range.

When thermal element 46 contracts and levers 53 and 51 move upward, as described above, the

tension of spring 53 increases. The tension of spring 63 is adjusted to limit the extent of upward movement of levers 53 and 57 and hence limit the closing movement of valve member 46.

The mechanism is preferably adjusted so that the upper limit of movement of valve member 44 is effected by spring 63 when thermal element it has contracted suiiiciently so that it no longer bears against knob 54 of lever 53. With valve member 44 in its uppermost position, which position is dependent upon the adjusted tension of spring 63, gas is delivered to burner M at a minimum pressure. The rate of flow of gas to burner it under these conditions may be adjusted so that heat of liquid is only supplied to the refrigerant in solution in generator l0 and refrigerant is heated to a temperature slightly below its vaporization temperature. When thermal element 45 expands and valve member 34 is moved downward from its uppermost position, gas is delivered to burner M at an increased pressure and additional heat is supplied to generator l0, whereby refrigerant is expelled out of solution and cold is immediately produced by cooling element 24.

During normal operation and when the valve member is moving toward and away from the valve seat formed by sleeve member 53, the spring ti keeps the levers 53 and 51 spread apart whereby movements of thermal element 46 are effectively transmitted to valve member 44. With movement of thermal element 46 the same movement is imparted to valve member 44 through the levers 53 and 51, so that no movement or sensitivity is lost. 1

When the valve member 44 is moved downward, the gas pressure on the discharge side of the valve member increases and an increased upward force is exerted by gas on the under-side of diaphragm 39. The tension of spring 6| is so adjusted that the separating force it imparts to levers 53 and 51 above the valve member corresponds to the diaphragm load required for the desired maximum'gas outlet pressure. Thus, when the gas outlet pressure on the discharge side of valve member and on the under-side of diaphragm 39 overcomes the tension at which spring 6| is adjusted, lever 51 moves toward lever 53 thereby permitting valve member 44 to move toward its closed position. In other words, the separating force of spring 6| normally keeps the levers 53 and 51 apart and stop 56 limits the spreading of the levers a fixed distance. However, when the pressure at which gas is delivered to burner l4 exceeds a predetermined maximum value, diaphragm 39 moves upward and overcomes the separating force exerted by spring 6|, whereby the levers 53 and 51 are pressed together. This may occur either through a relatively large downwardmovement of thermal element 46 or through an increase in gas inlet pressure to the control device l1.

When the levers 53 and 51 are pressed together, valve member 44 is moved upward to lower the pressure at which gas is delivered to burner l4. Irrespective of the position of thermal element 46, therefore, if the gas outlet pressure tends to exceed a predetermined maximum value, valve member 44 is moved toward its closed position to reduce the flow of gas and hence definitely limit the maximum rate of flow of gas to the burner.

While I have shown and described a particular embodiment of my improved control device, I do not wish to be limited to the particular arrangement set forth and illustrated in the drawings, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of the invention.

What is claimed is:

1. In refrigeration apparatus including a cooling element and a heat receiving, part, a fluid fuel burner for heating said part, a valve for controlling flow of fluid fuel to the burner, means operated by pressure of fluid fuel on the discharge side of said valve to move said valve toward its closed position, means operative in response to a temperature condition affected by said cooling element, and means for transmitting force resulting from movement of said temperature responsive means to cause movement of said valve toward its open position in opposition to said fuel pressure operated means, said transmitting means being eflective to transmit forces only up to a predetermined maximum, whereby the pressure on the discharge side of said valve cannot exceed said maximum.

2. The combination as set forth in claim 1 in which said transmitting means is adjustable to vary said maximum pressure.

3. The combination as set forth in claim 1 in which said transmitting means includes a spring.

4. The combination as set forth in claim 1 in which said transmitting means is a spring, and means for adjusting the stress on said spring to vary said maximum force.

5. The combination as set forth in claim 1 in which said transmitting means includes two levers, resilient means urging said levers apart, and a stop to limit separation of said levers.

6. The combination as set forth in claim 1 in which said fuel pressure operated means is a diaphragm subjected on one side to the pressure of liquid fuel on the discharge side of said valve.

7. The combination as set forth in-claim 1 which also includes a resilient element connected and arranged to oppose closing movement of said valve and effective to limit closing of said valve to a position at which the fuel pressure on the discharge side of said valve is ata predetermined minimum.

8. The combination as set forth in claim 1 also including a spring connected and arranged to oppose closing movement of said valve and effective to limit closing of said valve to a position at which the pressure on the discharge side of said valve is at a predetermined minimum, and means for adjusting said spring to vary said minimum.

9. In refrigeration apparatus including a cooling element and a heat receiving part, a fluid fuel burner for heating said part, a valve for controlling flow of fluid fuel to the burner, means responsive to pressure of fluid fuel on the discharge side of said valve urging said valve toward its closed position, means operative responsive to a temperature condition affected by said cooling element for operating said valve, and a spring connected and arranged to oppose closing movement of said valve and effective to limit closing of said valve to a position at which the fluid fuel pressure on the discharge side of said valve is at a predetermined minimum.

10. The combination as set forth in claim 9 also including means to adjust said spring to vary said minimum.

SVEN W. E. ANDERSSON. 

